Tufting machine knife block



June 4, 1968 J. A. COBBLE. sR.. ETAL. 3,336,398

TUFTING MACHINE KNIFE BLOCK Original Filed Dec. 29, 196-1 2 Sheets-Sheet 1 MHZ PRIOR 0P7 0 FAQ INVENTORS MJ MM ATTORNEYA June 4, 1968 J. A. COBBLE, sR.. ETAL 3,336,398

TUFTING MACHINE KNIFE BLOCK Original Filed Dec. 29, 1964 2 Shets-Sheet 2 NZ Z INVENTOR JAMES H. 6.05815, 81?. JAMES l4. COBB,JH.

ATTORNEYS United States Patent 3,386,398 TUFTING MACHINE KNIFE BLOCK James A. Cobble, Sr., Harrison, and James A. Cobble, Jr.,

East Chattanooga, Tenn., assignors to Southern Machine Company, Inc., Chattanooga, Tenn., a corporation of Tennessee Continuation of application Ser. No. 421,867, Dec. 29, 1964. This application Dec. 13, 1966, Ser. No. 601,432

11 Claims. (Cl. 83-700) ABSTRACT OF THE DISCLOSURE A knife block for a tufting machine comprising: an elongated channel-shaped body having a web and first and second flanges extending along opposite sides of said web for slidably receiving a tufting knife; an elongated bore extending transversely through said first flange; a slot having a larger cross section than said bore, formed through said knife block and communicating with said bore; an insert received in said slot for sliding movement therein transversely of the knife block; and an elongated operator extending through said bore, said element having an inner end portion engaging said insert so that when said elongated operator is moved transversely of the knife block along its own longitudinal axis said insert will be urged toward said web to engage the adjacent edge of a tufting knife received in said knife block.

This is a continuation of application Ser. No. 421,867, filed Dec. 29, 1964.

The present invention relates to textile machinery and more particularly to an improved knife block assembly especially useful in tufting machines for producing cut pile carpeting or the like.

In producing tufted carpeting for instance on machinery similar to that disclosed in Cobble et al. United States Patent 2,977,905 a loose woven backing fabric is fed, usually in an indexing fashion across a bed plate beneath a transverse row of vertically reciprocable needles operating in unison. Each needle is threaded with an elongated fiber body such as yarn fed from a rotatable package and upon each descent of the needles through the backing fabric an elongated loop of yarn is left depending beneath the backing fabric by each needle.

In order to ensure that the loops are not pulled back through the backing fabric as the needles ascend, each loop is usually caught, while the needles are still protruding through the backing fabric by a hook-like looper. There may conveniently be one looper for each needle, all of the loopers being mounted on a horizontal, transversely extending vertically oscillatable bar, driven by a cam or the like in syncronism with the operation of the needles.

Where cut pile carpeting rather than looped pile carpeting is desired usually a plurality of loop cutting knives are mounted on the tufting machine itself to avoid the waste which would result were the loops necessarily sheared subsequent to the production of the carpeting rather than being cut as they are formed.

The loop cutting knives are preferably mounted in knife blocks, the knife blocks being in turn mounted on an elongated vertical-1y reciprocable bar adjacent the looper carrying bar. Preferably, the knives and loopers are so arranged on their respective bars that each generally vertically upwardly directed knife resiliently bears against a looper, the loopers having a flat side edge so that the pile loops are cut scissors fashion between the knives and the looper flat surfaces.

For the sake of economy and ease of replacement, it is often the case that knife blocks are designed to 3,386,398 Patented June 4, 1968 "ice each carry more than one knife, for instance two knives in side by side relationship. Because of the scissors action involved in cutting pile loops as above-mentioned it is inevitable that knives will wear out and need replacement. Especially where the tufting machines are large, for instance as large as those which produce a continuous 15 foot width of tufted carpet and utilize 1200 knives mounted two each in 600 knife blocks, there has been a considerable need present for knife blocks which are themselvesdurable and which will allow rapid removal and replacement of worn or broken knives with a minimum of down time.

It is therefore an object of the present invention to provide a knife block assembly which will receive knives which have not been machined to so close a tolerance as has been necessary with prior art knife blocks.

A further object of the invention is to provide a knife block assembly from which individual knives can be easily and rapidly replaced and which is itself durable.

Another object of the present invention is the provision of a knife block assembly which can grip and support a plurality of knives even though they have small differences in thickness and widths.

Yet another object of the invention is the provision of a knife block assembly which can grip and support two knives in a side by side relationship, the gripping of both knives being effected by a single threaded element.

These and other objects of the present invention, the principles and scope of applicability thereof will become more clearly apparent from the following detailed description relating to preferred embodiments of the knife block assembly illustrated in the attached drawings.

In the drawings:

FIGURE 1 is a side elevation view of a representative prior art knife block;

FIGURE 2 is a fragmentary perspective of tufting apparatus including a knife block assembly embodying the principles of the present invention;

FIGURE 3 is a side elevation view of the knife block of FIGURE 2;

FIGURE 4 is a top plan view of the knife block of FIGURES 2 and 3;

FIGURE 5 is a transverse sectional view taken along line 55 of FIGURE 3;

FIGURE 6 is a sectional view taken substantially along the line 6-6 of FIGURE 3;

FIGURE 7 is a side elevation view, similar to FIG- URE 3 showing a modification of the knife block of the invention; and

FIGURE 8 is a fragmentary sectional view taken substantially along line 8-8 of FIGURE 7.

A typical prior art knife block 10 shown in FIGURE 1 is adapted to receive a pair of knives in side by side relationship in the two channels 12, one of which is on each side of the block 10'. The knives (not shown) are slidably received upwardly from the end 14 and are held in place by tightening the two screws 16. The screws 16 bear against the surfaces 18 of the saw cuts 20 causing the block portions 22 between the saw cuts 20 and 24 to deflect rearwardly thus reducing the width of the saw cuts 24 and of the channels 12. The knives are removed by loosening both screws 16. Unfortunately the portions 22 usually are deflected beyond their elastic limit in the tightening operation and are permanently bent as at 26 so that when the screws 16 are loosened for removal and replacement of the knives, the operator experiences great difficulty in attempting to disengage the knives.

In using knife blocks such as 10, knives must hemachined to close width and thickness tolerances. If a relatively wide and a relative narrow blade were slid into 3 the channels 12 and the screws 16 tightened it can be easily seen that the surfaces 28 of the channel 12 receiving the wider knife would be forced into engagement with the wider knife before the narrower knife had been contacted by the corresponding surface of the narrower knife. In other words, one knife would be secured in position, but the other would still be loose and liable to dropout. The two vertically spaced screws 16 are both necessary in this prior art knife block to minimize this problem.

Of course, more forceful turning of the screws 16 could cause the surfaces 28 to engage the second narrower knife also, but this would cause the skewing of the portions 22 and preclude the block from being used thereafter with knives having a substantially different proportional relationship to the skewed portions 22.

The essence of the present invention is the provision in a knife block of a rockable, slidable insert which is urged toward the channels by a threaded member and is free to rock to accommodate and secure in place knives of varied dimension, yet maintain its ability to receive knives of other dimension within a wide tolerance.

One preferred knife block according to the present invention is shown at 30 in FIGURES 2 through 6. As best seen in FIGURES 3 .and 4 the block 38 is generally a rectangular solid having rectangular sides 32 and 34, a top end 36- and a bottom end 38, front surface 40' and rear surface 42.

An undercut channel 44 is formed in the block side 32 extending vertically between the ends 36 and 38. A similar undercut channel 46 is formed in the block side 34. Where the block 30 is to be mounted at an angle other than a right angle to the bar 48 shown in FIGURE 2, one of the channels 44 or 46 may be offset slightly toward the front of the block to compensate for the mounting angle.

Each channel 44, 46 has a laterally inner surface 50 which is generally parallel to the sides 32, 34, side walls 52 which are generally parallel to the front and rear block surfaces 40, 42 and cantilevered overhanging portions 54. The latter are defined at the outer laterally extent of the sidewalls 52 by inwardly facing surfaces 56 which are generally parallel to the surface 50, edges 58 which are generally parallel to the side walls 52, and the block side surface 32 or 34. In other words, the portion of the block between the surfaces 50 comprises a flat elongated web; a pair of flanges thicker than the web extends along opposite sides of the web. One of these flanges is shown at 62, 52, 52, 54, 54, 56, 56 in the bottom portion of FIGURE 4, and the other is shown at 42, 52, 52, 54, 54, 56, 56 in the top portion of FIGURE 4. The interior surfaces of these two flanges are undercut flush with the surfaces 50 of the web to form four undercut grooves 52, 56.

As shown in FIGURE 3 an elongated slot 60 is formed through the block 30-, the slot being positioned so that it lies partly through the portion 62 of the block, in front of the channels 44, 46 and partly through the channels 44, 46. In the embodiment 30, a pair of vertically spaced, generally horizontally extending bores 64 are formed in said block beginning at the front 40 and extending rearwardly so as to intersect the slot 60 and terminate in sockets 66 centrally of the block 38 and between the channel surfaces 50.

An insert 68 of a thickness approximating that of the block 30, but a length and width somewhat smaller than the slot 68 is mounted in the slot 68 by a pair of roll pins or the like 70 received in the bores 64 and sockets 66. As shown best in FIGURES 3 and 6 the insert 68 is preferably of generally H-shaped longitudinal cross-section, a pair of recesses 72 being formed in the insert from the upper and lower ends 74, 76 thereof. As is apparent from FIGURE 6, the pins 78 extend transversely through the recesses 72, but because the pins 70 are spaced from one another a distance greater than the closest approach of the recesses to one another and because the 4 recesses are substantially broader than the thickness of the pins 70, the insert can rock a substantial amount on its mounting to accommodate knives 78 of varying size as is illustrated best in FIGURE 5.

To mount knives 78 in the knife block holder 30, the single screw 80 which is received in a threaded bore 82 intersecting the block front 40 and slot 60 to bear against the front surface 82 of the insert, is threaded outwardly to allow the insert to slide toward the front 40 of the block. Two knives 78 are then inserted and slid one each into the channels 44, 46 from the bottom end 38 of the block 38 until they reach the position shown in FIGURE 2. The single screw 80 is then threaded inwardly the inner end 84 thereof bearing against the front surface 82 of the insert 68, thus moving the insert toward the channels until the rear surface of the insert 68 firmly abuts both of the knives 78 and secures them in the channels 44, 46.

As best seen in FIGURE 2, the block 30 is preferably mounted on a bar 48 disposed beneath looper carrying bar 88. Each looper carried on the looper bar 88 is adapted to engage the side of a knife 78 near its upper extent thus exerting a bending stress on each knife 78. The knives 78 and loopers 90 when oscillated in vertical planes with respect to one another by their respective carrying bars effect between them a scissors action as discussed above which cuts the pile loops.

When a single knife 78 is to be removed the screw 89 is loosened and the knife pulled downwardly by the end 92 thereof, from the channel 44 or 46. The knives 78 may conveniently have a transversely extending hole 94 formed therethrough near the end 92 so that a hooked element can be inserted in the hole 94 to assist in pulling the knife from the channel. In this example the knife which is not being replaced remains in position even though the screw 80 has been loosened by virtue of its bending engagement with a looper 90 as aforementioned.

If both knives are to be replaced, it can be seen that it would be possible for the insert 68 to slide inwardly on the pins 70 and possibly jam against the upper end of the new knives 78 as they are being inserted. To effectively preclude this possibility, the insert 68 is preferably relieved adjacent its lower rear region so as to present a ramp-like downwardly facing, upwardly inclined surface 96 to the incoming knives. Accordingly, if the insert 68 has slipped inwardly, the upper ends 98 of the knives 78 being inserted will engage the surface 96 and drive the insert forwardly until its forward surf-ace 82 abuts the inner end 84 of the screw 80.

It should be readily observable especially from FIG- URE 5, that knives of differing dimension within a wide tolerance are mountable using the holder 30 thus allowing knives machined to considerably rougher tolerances, and thus lower cost to be used. Additionally, it should be noticed that effective subsequent use of the block 30 with a second pair of knives having a different dimension difference is not made less likely by the dimensional difference of the first pair of knives employed because tightening of the insert against the first pair does not permanently deform the block as with prior art knife blocks, it only rocks the insert 68.

A second embodiment of the knife block according to the invention is illustrated at 100 in FIGURES 7 and 8. Most of the elements of the block 100 are identical with those of the block 30 and so are numbered accordingly.

The major distinction of the block 100 is the difference in the mounting of the rockable, slidable insert 68'. Rather than being mounted on pins the insert 68' is associated with the block 100 by way of a tongue and groove arrangement 102. The latter is shown consisting of a relatively thin tongue 104 on the upper and lower ends of the insert 68 and a wider groove 106 in the upper and lower ends 198, 110 of the slot 112. The insert 68' is slidable rockable in the slot 112 similarly to the action of the 1n sert 68 in the slot 60 of the block 30.

As shown in FIGURE 8, for ease of assembly of the insert 68' in the block 100 the insert 68 may be formed in two sections 114, 116 each being about half the thickness of the block 106 and one section, 114, carrying the tongues 104. The sections 114, 116 can be pinned together as with pins 118 after they are positioned with respect to the groove 106 as shown in FIGURES 7 and 8.

Although the insert 68' and slot 112 have been shown being generally rectangular, it should be obvious that other shapes could be employed, for instance the insert and slot could have complementary halfmoon shapes.

Although the major portion of the blocks 30 and 100 have been shown machined as a single piece it should be understood that they could be fabricated from a plurality of pieces and while the screw 80, slots 60, 112 and inscrts 68, 68' have been shown positioned generally midway between the top and bottom of their respective blocks 30, 100 it should be realized that this positioning is not considered elemental to their proper functioning. Although the knife blocks shown are especially adapted to support two knives it is clear that the principles employed could be used to construct similar blocks for supporting a single knife or several knives. In this latter case it might be necessary to mount a resilient pad against the front surface of the rock-able slidable insert so that sufiiciently forceful contact with all of the knives regardless of their difference in width would be assumed.

it should now be clear that the two embodiments of the invention discussed clearly illustrate the accomplishment of all of the objects of the invention and make its principles quite understandable. Because the embodiments shown can be modified somewhat Without departing from these principles, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the appended claims.

We claim:

1. A knife block comprising: a body portion; means defining a knife receiving channel in said body portion constructed and arranged to longitudinally receive a knife which has two opposite faces, two opposite ends and two opposite longitudinal edges extending between the ends at opposite margins of the faces; an insert mounted in said body adjacent said channel; means for selectively moving said insert toward and away from said channel to increase and decrease the effective width of the channel respecting the edge-to-edge dimension of the knife whereby the insert is movable toward and away from contact with an edge of the knife; further comprising means defining a second knife receiving channel in said body, spaced laterally from the first-mentioned channel, said insert being received in means defining a laterally extending slot through said body portion; said insert being selectively movable toward and away from said second channel to increase and decrease the effective width of the channel.

2. A knife block as set forth in claim 1 wherein said insert is substantially shorter than said channels.

3. A knife block as set forth in claim 1 including mounting means for said insert, comprising: a pair of vertically spaced generally horizontally extending pins extending across said slot, said insert having means thereon at least partially surrounding each of said pins; said last-mentioned means having greater width than said pins whereby said insert is both slidable along said pins and rockable with respect to said pins to accommodate knives of varying width in said channels.

4. A knife block as set forth in claim 3 wherein said insert includes means at the lower extent thereof defining a downwardly facing surface which is inclined toward said channels whereby knives being slidably inserted in the channels may engage said surface to urge said insert away from said channels and thus prevent jamming of the knives thereagainst.

5. A knife block as set forth in claim 1 including mounting means for said insert, comprising means defining cooperating tongue and groove means on the periphery of said slot and said insert, the grooves being wider than the tongue whereby the insert is both slidable along said tongue and groove means and rockable with respect to said body to accommodate knives of varying width in said channels.

6. A knife block as set forth in claim 5 wherein said insert includes means at the lower extent thereof defining a downwardly facing surface which is inclined toward said channels whereby knives being slidably inserted in the channels may engage said surface to urge said insert away from said channels and thus prevent jamming of the knives thereagainst.

7. A knife block as set forth in claim 1 wherein said selectively-moving means comprises means defining a threaded bore in said body communicating between the front of the body and said slot, and a threaded element threadably received in said bore for engagement with said insert.

8. A knife block as set forth in claim 7 wherein said insert has a forwardly presented surface and said threaded element abuts said forwardly presented surface to drive the insert toward the channels.

9. A knife block as set forth in claim 1 additionally including a generally horizontally extending rod secured to said body and extending from the rear thereof for mounting said knife block on a knife block bar.

10. A knife block for a tufting machine comprising:

(a) an elongated channel-shaped body having a web and first and second flanges extending along opposite sides of said web for slidably receiving a tufting knife;

(b) an elongated bore extending transversely through said first flange;

(0) a slot having a larger cross-section than said bore, formed through said knife block and communicating with said bore;

(d) an insert received in said slot for sliding movement therein transversely of the knife block; and

(e) an elongated operator extending through said bore, said operator having an inner end portion engaging said insert so that when said elongated operator is moved transversely of the knife block along its own longitudinal axis said insert will be urged toward said web to engage the adjacent edge of a tufting knife received in said knife block.

11. The knife block of claim 10 in which said elongated operator is threadably advanceable in said knife block, and said slot and insert include cooperating interfitting means for guiding sliding movement of said insert transversely of said knife block.

References Cited UNITED STATES PATENTS 1,214,497 2/1917 Armstrong 29-96 216,800 6/1879 McNiece -108 1,877,211 9/1932 Webster 30-304 1,984,500 12/1934 Tautz 30-329 ANDREW R. JUHASZ, Primary Examiner. 

